Chemistry:1,2-Dibromoethylene
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| Preferred IUPAC name
1,2-Dibromoethene | |||
| Identifiers | |||
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| Properties | |||
| C2H2Br2 | |||
| Molar mass | 185.846 g·mol−1 | ||
| Appearance | colorless liquid | ||
| Density | 2.246 g/cm3 | ||
| Boiling point | 110 °C (230 °F; 383 K) | ||
| Hazards | |||
| Main hazards | Toxic | ||
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| GHS Signal word | Danger | ||
| H301, H314, H315, H319, H335 | |||
| P260, P261, P264, P270, P271, P280, P301+310, P301+330+331, P302+352, P303+361+353, P304+340, P305+351+338, P310, P312, P321, P330, P332+313, P337+313, P362, P363, P403+233, P405, P501 | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
| Infobox references | |||
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-1,2-Dibromoethene.png)
1,2-Dibromoethylene, also known as 1,2-dibromoethene and acetylene dibromide, is a dihalogenated unsaturated compound with one bromine on each of the two carbon atoms. There are two isomers of this compound, cis and trans. Both isomers are colorless liquids.
Synthesis
1,2-dibromoethylene can be synthesized by halogenation of acetylene C2H2 with bromine Br2.[1] In order to prevent the formation tetrahalogenated compounds, acetylene is used in excess, with Br2 as the limiting reagent.
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Alternately, halogenation of this kind could also be achieved through the use of two equivalents of N-bromosuccinimide and lithium bromide (LiBr). N-Bromosuccinimide provides Br+ as an electrophile, which is followed by Br− from LiBr.[2]
References
- ↑ "Chapter 9: Addition Reactions of Alkynes". McGraw-Hill. http://www.mhhe.com/physsci/chemistry/carey/student/olc/ch09additionreactionsofalkynes.html.
- ↑ Shao, L.-X.; Shi, M. (2006). "N-Bromosuccinimide and Lithium Bromide: An Efficient Combination for the Dibromination of Carbon–Carbon Unsaturated Bonds". Synlett 2006 (8): 1269–1271. doi:10.1055/s-2006-941558. https://www.thieme-connect.de/products/ejournals/pdf/10.1055/s-2006-941558.pdf.
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